Determination of water content in bee’s pollen samples by Karl Fischer titration

Gergen, I.; Radu, Florina; Bordean, Despina-Maria; Isengard, Heinz‐Dieter

doi:10.1016/j.foodcont.2004.09.018

Cited by 15 publications

(15 citation statements)

References 4 publications

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“…The quantity of water in bee pollen varies between 4 and 10%, and this water content ensures good preservation over time and the nondegradation of organic compounds, which consequently maintain original inherent properties (Gergen et al, 2006;Nogueira et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Characterization of phenolic profile alterations in metal-polluted bee pollen via capillary electrophoresis

Mejías

Gómez²,

Gareil

et al. 2018

Ciencia e investigación agraria

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E. Mejías, C.J. Gómez, P. Gareil, N. Delaunay, and G. Montenegro. 2018. Characterization of phenolic profile alterations in metal-polluted bee pollen via capillary electrophoresis. Cien. Inv. Agr. 45(1): 51-63. Bee pollen is a conglomerate of plant pollens, and its nutritional contents include bioactive compounds with antioxidant/antiradical potentials. These potentials are conditioned by botanical origin. In Chile, the native flora is diverse and promising in terms of bioactive compounds, but many plants grow in metal-polluted areas. The associated bioaccumulation could negatively affect the antioxidant/antiradical abilities of bee pollen. To assess the relationship between the bioaccumulation of metals and the antioxidant activity of pollen, complete bee pollen was collected near and far from the Llaima Volcano, albeit in ranges that ensured the same botanical origins. Mellisopalynological analysis determined Escallonia rubra pollen was the most abundant native flora in complete bee pollen. Therefore, E. rubra pollen collected near and far from the Llaima Volcano was evaluated for the following: phenolic compounds via colorimetric assays; antioxidant activity via ferric reducing/antioxidant power assays; antiradical activity via 1,1-diphenyl-2-picrylhydrazyl radical assays; and metal contents via inductively coupled plasma optical emission spectrometry. Llaima samples had higher Cu and Fe but lower Mn contents and lower antioxidant and antiradical capacities than did the control samples. These results were supported by subsequent fortification assays in Llaima E. rubra samples. In fortified samples with significantly higher metal contents, antiradical and antioxidant abilities decreased. Moreover, shifts in migration times were found for naringenin, rutine, and caffeic acid after capillary electrophoresis (CE) analysis in fortified samples. In conclusion, the results indicated an inverse correlation between metal contents and antioxidant/ antiradical potentials in bee pollen.

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Section: Introductionmentioning

confidence: 99%

Characterization of phenolic profile alterations in metal-polluted bee pollen via capillary electrophoresis

Mejías

Gómez²,

Gareil

et al. 2018

Ciencia e investigación agraria

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“…Karl Fischer titration was performed according to the method proposed by Gergen et al (2006), using an automatic METROHM Titrino 785 titrator (Herisau, Switzerland). Titrations were performed using apura Titrant 5 (Merck) as the titrant and a mixture of methanol p.a.…”

Section: Karl Fischer Titrationmentioning

confidence: 99%

“…According to Isengard, Schultheib, Radovic & Anklam (2001) and Isengard (2001), the Karl Fischer titration may be used as a reference method to determine the water content in products with a complex composition, such as bee pollen, provided that it is preceded by experiments to determine optimal conditions for analysis, such as the most appropriate extraction temperature, the best solvent to dissolve the sample, and the particle size of the sample (Gergen, Radu, Bordean & Isengard, 2006). The major advantages to this method are: measurements performed in a few minutes, minimum sample preparation, and no loss of volatile compounds (Bastos, Rocha, Cunha, Carvalho & Torres 2006;Bonvehi & Casanova, 1987;Gergen et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The major advantages to this method are: measurements performed in a few minutes, minimum sample preparation, and no loss of volatile compounds (Bastos, Rocha, Cunha, Carvalho & Torres 2006;Bonvehi & Casanova, 1987;Gergen et al, 2006). Bonvehi & Jordá (1997) emphasize that the outstanding accuracy of the Karl Fischer method makes it as the obvious method of choice for the determination of the moisture level in honeybee-collected pollen.…”

Section: Introductionmentioning

confidence: 99%

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Determination of water content in Brazilian honeybee-collected pollen by Karl Fischer titration

Morgano¹,

Milani²,

Martins

et al. 2011

Food Control

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a b s t r a c tThis paper assesses the performance of a chemical method based on the Karl Fischer titration to determine the water content in samples of dehydrated honeybee-collected pollen. The following analysis parameters were investigated: extraction temperature, particle size, reaction time, and weight of a dried pollen sample. After optimization, the method was used to determine the water content of 154 samples of dried honeybee-collected pollen from different geographical regions of Brazil. The Karl Fischer titration method, performed using a solvent mixture of methanol and n-octanol (1:1 v/v) at 50 C on pollen particles 600 mm in size produced the best results. Mean values for water content of the 154 samples of dried honeybee-collected pollen from 12 Brazilian regions ranged from 3% to 9%.

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“…The electrochemical approach is generally highly reliable; however, in some cases, especially for relatively small water concentrations and highly lipophilic, aprotic solvents, it may potentially be sensitive to, e.g., sample acquisition due to tendency of water to spontaneously accumulate close to more hydrophilic surfaces-e.g., glassware. This effect may result in inaccurate determination results (Dantan et al 2000;Gergen et al 2006). Moreover, the Karl Fischer titration method is difficult to be implemented as a part of, e.g., industrial or technological process, or to be used to continuously monitor any occurrence of water in sample media.…”

Section: Introductionmentioning

confidence: 99%

Improving Fluorometric Determination of Water Content in Aprotic Solvents

et al. 2017

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A fluorometric method allowing quantification of minute amounts of water in highly lipophilic solvents is proposed. This approach takes advantage of resonance energy transfer between 4-methylumbelliferone and Sudan I. The conditions required to observe effective energy transfer have been elucidated. The emission band of the donor molecule (4-methylumbelliferone) depends strongly on the water content-its position is affected by protolytic reactions occurring between the fluorescent dye and water in lipophilic solvent media. In consequence, the extent of overlap between the emission band of the donor and absorption peak of the acceptor scales with the water concentration. The sensitivity of this optical system can be considerably increased by addition of organic bases. The dependence of the emission band of 4-methylumbelliferone/Sudan I system on minute amount of water present in lipophilic solutions opens up possibility of determination of water content in these media at the unique wavelength, in a turn on mode. The presented system was successfully applied to determine water in model commercial oil samples. It was shown that using herein proposed method the increase of water contents in the sample can be observed as increase of the emission intensity, despite the native fluorescence of the vegetable oil samples. For these samples, a good correlation with golden standard Karl Fischer titration was obtained.

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Determination of water content in bee’s pollen samples by Karl Fischer titration

Cited by 15 publications

References 4 publications

Characterization of phenolic profile alterations in metal-polluted bee pollen via capillary electrophoresis

Characterization of phenolic profile alterations in metal-polluted bee pollen via capillary electrophoresis

Determination of water content in Brazilian honeybee-collected pollen by Karl Fischer titration

Improving Fluorometric Determination of Water Content in Aprotic Solvents

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